How Can I Last Longer During Sex I Cum Too Fast Im A Dude

So I've been with her for about a year, little over now and this problem is ongoing, I can last about 15 to 20 seconds when in her. Anyone ever been through this, how did you get through it and fianlly last longer? I've tried medicine and doctors and nothing seems to work to the point where we dont really want to do it a lot anymore.
let me clarify. Doggy I can last plenty of time but missionary is the problem.

If it's good then the relationship may last longer, and if it sucks it may not last as long.
In my relationship, I definitely think that overall I have a stronger sex drive than my boyfriend.

Give her loving licks and kisses between the legs. Give her a full-body massage. Bring a vibrator (pocket rocket) to bed.

..Im used to 20 mins reg....none stop...and thats at least 4 times a night.!So my Im very lucky!...and I wanna hold on to him!

Holding period depends from person to person and from situation to situation, with time u'll settle with sex it will surely lengthen, and as far as satisfying sex is concerned pamper her with a good foreplay she will just love it

Here is one exercise that my boyfriend had tried during masturbation and it helps the situation so much when he is doing it with me! (not overnight, but gradually)
Stop during masturbation
Begin masturbating as normal. As you near orgasm, stop masturbating. Don't go over the edge. Let your tension unwind. When you have relaxed enough, masturbate again until you feel the onset of orgasm, then stop. Repeat this for as long as you like. This is the simplest way to keep sex going. First you must learn to recognize pre-orgasm, and to stop immediately. Otherwise sex is over. Without the pre-orgasm, male orgasm control falls apart. Practice first on your own. You will learn quicker this way. Your concentration will not be broken by external diversions. Once you have practiced stopping at pre-orgasm on your own, try it during sex.
There are some other breathing techniques that can help in calming your excitement and get going with your performance. And remember, always divert your concentration elsewhere when you are about to come. To name a few: as fingering her, continue with your foreplay, going down on her or changing a new sex position.
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Masturbate, not even kidding.
Try to restrain yourself when you're about to ejaculate, it'll increase your endurance a teeny bit each time. Eventually it all adds up to a good deal of resiliance.

Do some of the work yourself. Stop for awhile so he can catch his breath. Think of it as somewhat like a boxing match, you know, three minutes and a break of one minute, three minutes and a break for one minute et cetera et cetera et cetera.
Eventually you will get a TKO or Knockout.

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